Multicomponent system that can be cured thermally or by actinic radiation, method for producing the same and the use thereof

ABSTRACT

Multicomponent system curable thermally and with actinic radiation, comprising A) an isocyanate-reactive binder comprising A1) at least one unsaturated polyester whose molecule contains on average at least one group that can be activated with actinic radiation, of the formulae I, II and/or III  
                 
 
     wherein n is an integer from 1 to 10; and A2) at least one binder, different than (A1), whose molecule comprises on average at least two isocyanate-reactive functional groups, and/or A3) at least one binder, different than (A1), whose molecule comprises on average at least one isocyanate-reactive functional group and at least one reactive functional group having at least one bond that can be activated with actinic radiation, and B) a crosslinker comprising B1) at least one polyisocyanate and/or B2) at least one polyisocyanate whose molecule comprises on average at least one reactive functional group having at least one bond that can be activated with actinic radiation.

[0001] The present invention relates to a novel multicomponent systemcurable thermally and with actinic radiation. The present inventionfurther relates to a process for producing the novel multicomponentsystem curable thermally and with actinic radiation. The presentinvention additionally relates to the use of the novel multicomponentsystem curable thermally and with actinic radiation for priming plasticsparts.

[0002] The coating of plastics parts is becoming increasingly important,especially in the motor vehicle industry. Here, a segment showingparticularly rapid growth is that of mounted plastics components.However, the coating of plastics still causes great problems, broughtabout in particular by the variable surface smoothness of the plasticsparts, the adhesion of coatings to different plastics surfaces, and theformation of gas bubbles and holes in the coatings on curing.

[0003] In order to solve these problems, it is common to apply specialprimers intended to compensate the unevennesses of the plastics surfacesand ensure that the coatings adhere to the plastics surfaces. For thispurpose it is common to use what are known as multicomponent systems,where owing to its high reactivity the crosslinker component is storedseparately from the binder component prior to application. Examples ofsuch multicomponent systems are those are known as polyurethane systems,where the binding component comprises isocyanate-reactive functionalgroups and the crosslinker component comprises polyisocyanates.

[0004] The disadvantage of these multicomponent systems is theircomparatively long reaction time, unacceptable especially in OEMautomotive finishing. Although the reaction time could be shortened byapplying heat, to do so would reintroduce the problem of formation ofbubbles. The surface defects caused by the gas bubbles in the primerswould then have to be made good by sanding, which is laborious andexpensive.

[0005] Multicomponent systems curable thermally and with actinicradiation, and their use as coating materials, are known, for example,from European Patent Application EP 0 928 800 A1. The known coatingmaterials comprise a urethane (meth)acrylate, containing (meth)acrylategroups and free isocyanate groups, a UV initiator which initiatesfree-radical polymerization (photoinitiator), and an isocyanate-reactivecompound. Suitable isocyanate-reactive compounds include polyols such aspolyesters formed from diols and triols with dicarboxylic acids,hindered amines formed from maleic esters and cycloaliphatic primarydiamines, polyether polyols, or hydroxyl-containing (meth)acrylatecopolymers. The priming of plastics parts is not addressed in theEuropean Patent Application.

[0006] German Patent Application DE 199 20 799, unpublished at thepriority date of the present specification, describes a multicomponentsystem curable thermally and with actinic radiation. As its bindercomponent it comprises a hydroxyl-free polyurethane having pendantacrylate groups, and a polyester polyol, and as its crosslinkingcomponent, a polyisocyanate containing acrylate groups. Themulticomponent system is used to seal sheet molded compounds (SMC) andbulk molded compounds (BMC). There is no use, however, of anycrosslinker components or binder components which includedicyclopentadienyl groups and/or endomethylenetetrahydrophthalic acidgroups.

[0007] German Patent Application DE 199 03 725, unpublished at thepriority date of the present specification, describes a coating materialcomprising an essentially hydroxyl-free, unsaturated polyester havingdicyclopentadienyl groups and/or endomethylenetetrahydrophthalic acidgroups and a hydroxyl-free polymer, materially different from thepolyester, which may include the aforementioned groups. It is mentionedin passing in the application that the coating material may becocrosslinked with polyisocyanates. Details of how this is to be doneare not given. Moreover, the known coating material is said to be usedin particular as a powder coating material.

[0008] It is an object of the present invention to find a newmulticomponent system, curable thermally and with actinic radiation,from which the disadvantages of the prior art are now absent and whichinstead is easy to apply, leads rapidly and reliably at comparativelylow temperatures to coatings, especially primer coats on plastics parts,which are free from surface defects such as bubbles and cracks, provideoutstanding compensation of unevennesses in plastics surfaces, andexhibit excellent adhesion to the plastics surfaces and to coatingsapplied to the primer coats.

[0009] We have found that this object is achieved by the novelmulticomponent system, curable thermally and with actinic radiation,which comprises the following components:

[0010] A) an isocyanate-reactive binder component comprising

[0011] A1) at least one unsaturated polyester whose molecule contains onaverage at least one group that can be activated with actinic radiation,of the formulae I, II and/or III

[0012] (II), in which the index n is an integer from 1 to 10;

[0013]  and

[0014] A2) at least one binder, different than the polyester (A1), whosemolecule comprises on average at least two isocyanate-reactivefunctional groups,

[0015]  and/or

[0016] A3) at least one binder, different than the polyester (A1), whosemolecule comprises on average at least one isocyanate-reactivefunctional group and at least one reactive functional group having atleast one bond that can be activated with actinic radiation,

[0017]  and

[0018] B) a crosslinker component comprising

[0019] B1) at least one polyisocyanate and/or

[0020] B2) at least one polyisocyanate whose molecule comprises onaverage at least one reactive functional group having at least one bondthat can be activated with actinic radiation.

[0021] In the text below, the novel multicomponent system curablethermally and with actinic radiation is referred to as the“multicomponent system of the invention”.

[0022] Further subject matter of the invention will emerge from thedescription.

[0023] In the light of the prior art it was surprising and unforeseeableby the skilled worker that the object on which the present invention isbased might be achieved with the aid of the multicomponent system of theinvention. A particular surprise was that the multicomponent system ofthe invention, following its preparation, i.e., after the mixing of itscomponents, had a processing time or pot life which is long formulticomponent systems, and nevertheless, following application, curedrapidly at comparatively low temperatures without any risk of bubblesbeing formed.

[0024] In the context of the present invention, actinic radiation iselectromagnetic radiation such as near infrared (NIR), visible light orUV light or corpuscular radiation such as electron beams.

[0025] Curing with heat and actinic radiation is referred to below usingthe term commonly employed in the art, namely “dual cure”.

[0026] At the time of application, the multicomponent system of theinvention may be present in a variety of physical forms. For instance,it may be in the form of an aqueous solution or dispersion, an organicsolution or dispersion, an essentially water- and solvent-free, liquid100% system, an essentially water- and solvent-free, finely divided,solid powder coating material, or a powder coating dispersion (powderslurry). It is of advantage in accordance with the invention if themulticomponent system of the invention is in the form of a liquid 100%system.

[0027] The first essential constituent of the multicomponent system ofthe invention is at least one isocyanate-reactive binder component (A)which comprises at least one unsaturated polyester (A1) and at least onebinder (A2) and/or (A3) different than the polyester (A1).

[0028] In the context of the present invention, the term binder refersto oligomeric and polymeric resins, the oligomeric resins normallycontaining on average from 3 to 15 monomer units and the polymericresins normally contain on average more than 10, in particular more than15, monomer units per molecule.

[0029] The unsaturated polyester (A1) contains on average at least one,preferably at least two, group(s) of the formulae I, II and/or III thatcan be activated with actinic radiation. Preferably, the groups I and IIare incorporated into the unsaturated polyesters (A1) by way of thefollowing starting compounds IV to VIII:

[0030] (VI), in which the index n is as defined above,

[0031] (VIII), in which the index n is as defined above.

[0032] Preferred and easily obtainable are the esterlikedicyclopentadienyl (DCPD) adducts with polycarboxylic acids, assymbolized by the formulae V and VI. As a special case of these DCPDadducts there result adducts of maleic anhydride and water with DCPD, ofthe formulae VII and VIII. The use of such adducts produces particularlypreferred unsaturated polyesters (A1). Moreover,dihydrodicyclopentadienol IV is available commercially and may be usedin the synthesis of the polyesters (A1), thereby likewise introducingthe structural units I and II.

[0033] Where the polyesters (A1) contain double bonds in the polymerchain, e.g., as maleic or fumaric esters, grafting with cyclopentadieneproduces endomethylenetetrahydrophthalic acid structures III.

[0034] Examples of further suitable starting compounds for thepreparation of the polyesters (A1) are the following:

[0035] adipic acid, suberic acid, phthalic acid isomers,tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid,hexahydrophthalic acid, fumaric acid, maleic acid, itaconic acid,citraconic acid, trimellitic acid or pyromellitic acid;

[0036] ethylene glycol, polyethylene glycols, propylene glycol,polypropylene glycols, butanediol isomers, hexanediol, neopentyl glycol,trimethylolpropane, glycerol, pentaerythritol, bisphenol A orhydrogenated bisphenol A;

[0037] OH-polyfunctional polymers such as hydroxyl-modifiedpolybutadienes or hydroxyl-bearing polyurethane prepolymers and epoxyresins;

[0038] polyfunctional natural substances or derivatives thereof, such aslinseed oil fatty acid, dimeric and polymeric linseed oil fatty acid,castor oil, castor oil fatty acid; and/or

[0039] alkoxylated hydroxy-functional compounds such as the ethoxylationand propoxylation products of the abovementioned polyols.

[0040] Furthermore, the introduction of amide and imide structures intopolyesters (A1), in accordance with the patent applications DE 157 0 273A1 and DE 172 0 323 A1 is also known prior art.

[0041] The introduction of the structural units I and/or II takes placepreferably through the use of the above-described acidic esters V toVIII, especially VII and VIII, in the polycondensation.

[0042] A further possibility is to prepare polyesters (A1) with anexcess of acid and then to react them with DCPD. A high degree ofconversion generally necessitates the use of catalysts, an example beingboron trifluoride etherate. At relatively high temperatures andpressure, oligo-DCPD structures (structural unit II) are also formed.

[0043] Where the polyesters (A1) in this reaction contain double bondsin the polymer chain, e.g., as maleic or fumaric esters, grafting withcyclopentadiene produces endomethylenetetrahydrophthalic acid structuresVIII.

[0044] Also of particular importance are polyesters (A1) in accordancewith patent application DE 43 21 533 A1, which are obtained usinghydroxy-functional allyl ethers and have a particularly highphotosensitivity. Also of importance of polyesters (A1) whose carboxylgroups that have remained free during the polycondensation are reactedwith unsaturated epoxide compounds, preferably glycidyl (meth)acrylate;this measure, too, increases the photosensitivity.

[0045] The incorporation of photoinitiator groups II into the polyesters(A1) is possible, for example, by using benzophenonetetracarboxylicacid, benzophenonetetracarboxylic anhydride orbenzophenonetetracarboxylic esters or 4-hydroxybenzophenone in thepolycondensation. It is preferred in this case first to preparehydroxyl-terminated polyester precursors, using an excess of hydroxylcompounds, and to react these precursors withbenzophenonetetracarboxylic anhydride. In the course of this reaction,the benzophenone structures are incorporated in chain positions into thepolyesters (A1) and carboxyl groups are produced. It is likewisepreferred then to react these carboxyl groups with unsaturated epoxycompounds, preferably glycidyl (meth)acrylate.

[0046] The synthesis of the polyesters (A1), which satisfies specificrequirements in respect, for example, of hardness, elasticity, viscosityor softening point, takes place in accordance with rules known to theskilled worker, through selection of the structural components andestablishment of the degree of condensation. For preparing thepolyesters (A1) it is generally possible to employ the apparatus andtechniques described in detail in the standard work UllmannsEncyklopädie der technischen Chemie, 3rd Edition, Volume 14, Urban &Schwarzenberg, Munich, Berlin, 1963, pages 80 to 89 and pages 99 to 105,and in the following books: “Résines Alkydes-Polyesters” by J. Bourry,Paris, Dunod, 1952, “Alkyd Resins” by C. R. Martens, Reinhold PublishingCorporation, New York, 1961, and “Alkyd Resin Technology” by T. C.Patton, Interscience Publishers, 1962.

[0047] The polyester (A1) may be prepared with an excess of polyols, sothat it has free hydroxyl groups. Alternatively, the polyols and thepolycarboxylic acids may be present in a stoichiometric ratio in respectof the hydroxyl groups or carboxyl groups, except that they are notcondensed to completion, so that there are still free hydroxyl groupsand carboxyl groups. This has the advantage that the polyesters (A1) aswell are able to participate in the thermal crosslinking with theisocyanate groups of component (B) (dual cure).

[0048] The polyesters (A1) preferably have a hydroxyl number of from 20to 200, in particular from 30 to 120 mg KOH/g.

[0049] The proportion of the polyesters (A1) in the multicomponentsystems of the invention may vary very widely. It is preferably from 1to 60, more preferably from 2 to 55, with particular preference from 3to 50, with very particular preference from 4 to 45, and in particularfrom 5 to 40% by weight, based in each case on the solids of themulticomponent system of the invention.

[0050] In the context of the present invention, here and below, the term“solids” refers to that fraction of the multicomponent system of theinvention that remains as solids in the primer of the invention aftercuring.

[0051] The isocyanate-reactive binder component (A) further comprises atleast one binder (A2), which is different than the polyester (A1) andwhose molecule comprises on average at least one, in particular at leasttwo, isocyanate-reactive functional group(s).

[0052] Instead of the binder (A2) or in addition to it, theisocyanate-reactive binder component (A) comprises at least one binder(A3) which is different than the polyester (A1) and whose moleculecomprises on average at least one, in particular at least two,isocyanate-reactive functional group(s) and at least one, in particularat least two, reactive functional group(s) having at least one bond thatcan be activated with actinic radiation. In the text below the reactivefunctional groups having at least one bond that can be activated withactinic radiation are referred to for the sake of brevity as“radiation-active groups”.

[0053] The binders (A3) are of advantage in accordance with theinvention since they may be cured by the dual cure mechanism.

[0054] The binders (A2) and (A3) comprise the same oligomeric orpolymeric parent structures, as are described below.

[0055] Examples of suitable isocyanate-reactive functional groups arehydroxyl groups, primary and secondary, especially primary, amino groupsand/or thiol groups. Of these, hydroxyl groups are of particularadvantage and are therefore used with preference in accordance with theinvention.

[0056] In the context of the present invention, a bond that can beactivated with actinic radiation is a bond which on exposure to actinicradiation becomes reactive and, with other activated bonds of its kind,enters into addition polymerization reactions and/or crosslinkingreactions which proceed in accordance with free-radical and/or ionicmechanisms. Examples of suitable bonds are carbon-hydrogen single bondsor carbon-carbon, carbon-oxygen, carbon-nitrogen, carbon-phosphorus orcarbon-silicon single bonds or double bonds. Of these, the carbon-carbondouble bonds are particularly advantageous and are therefore used withvery particular preference in accordance with the invention. For thesake of brevity, they are referred to below as “double bonds”.

[0057] Accordingly, the radiation-active group which is preferred inaccordance with the invention contains one double bond or two, three orfour double bonds. Where more than one double bond is used, the doublebonds may be conjugated. In accordance with the invention, however, itis of advantage if the double bonds are present in isolation, inparticular each being present terminally, in the radiation-active group.It is of advantage in accordance with the invention to use two doublebonds and of particular advantage to use one double bond.

[0058] Furthermore, the binders (A3) contain on average at least one, inparticular at least two, radiation-active group(s). The functionalitychosen is guided on the one hand by the stoichiometric ratios of thestarting products of the binders (A3), which on the other hand areguided again by their intended applications.

[0059] Where on average more than one radiation-active group permolecule is used, the at least two radiation-active groups arestructurally different from one another or of the same structure.

[0060] If they are structurally different from one another, this meansin the context of the present invention that two, three, four or more,but especially two, radiation-active groups are used which derive fromtwo, three, four or more, but especially two, monomer classes.

[0061] Examples of suitable radiation-active groups are (meth)acrylate,ethacrylate, crotonate, cinnamate, vinyl ether, vinyl ester,dicyclopentadienyl, norbornenyl, isoprenyl, isopropenyl, allyl orbutenyl groups; dicyclopentadienyl, norbornenyl, isoprenyl, isopropenyl,allyl or butenyl ether groups, or dicyclopentadienyl, norbornenyl,isoprenyl, isopropenyl, allyl or butenyl ester groups, but especiallyacrylate groups.

[0062] The radiation-active groups are attached to the parent structureof the binder (A3) by way of urethane, urea, allophanate, ester, etherand/or amide groups. Urethane groups are particularly preferred.Suitable structures for this purpose are the following two linkingstructures IX and X:

[0063] Parent structure-NH—C(O)—O-radiation-active group (IX), and

[0064] Parent structure-O—(O)C—NH-radiation-active group (X).

[0065] Both linking structures IX and X or only one of them may bepresent in the binder (A3). In general, the structure IX is ofadvantage, owing to the larger number of available starting materialsand their comparatively greater ease of preparation, and is thereforeemployed with preference in accordance with the invention.

[0066] The radiation-active groups are attached terminally and/orlaterally to the parent structure. The type of attachment chosen isguided in particular by whether the reactive functional groups in theparent structure with which the starting materials of theradiation-active groups are able to react are located laterally orterminally. Owing to the lack of steric screening, terminalradiation-active groups frequently have a higher reactivity than lateralradiation-active groups and are therefore used with preference. On theother hand, however, the reactivity of the binder (A3) may be tailoredby way of the proportion of terminal and lateral radiation-activegroups, which is a further particular advantage of the multicomponentsystem of the invention.

[0067] The parent structure of the binders (A2) and (A3) is oligomericand/or polymeric. In other words, the binders (A2) and (A3) areoligomers or polymers or mixtures thereof.

[0068] The oligomeric or polymeric parent structure contains orcomprises aromatic, cycloaliphatic and/or aliphatic structures orstructural units. Preferably, it contains or comprises cycloaliphaticand/or aliphatic structures, especially cycloaliphatic and aliphaticstructures.

[0069] Examples of suitable aromatic structures are aromatic andheteroaromatic rings, especially benzene rings.

[0070] Examples of cycloaliphatic structures are cyclobutane,cyclopentane, cyclohexane, cycloheptane, norbornane, camphane,cyclooctane or tricyclodecane rings, especially cyclohexane rings.

[0071] Examples of aliphatic structures are linear or branched alkylchains having 2 to 20 carbon atoms, or chains as result from the(co)polymerization of olefinically unsaturated monomers.

[0072] The parent structure may further comprise olefinicallyunsaturated double bonds.

[0073] The parent structure may further comprise chemically bondedstabilizers. If used, they are present in the binder (A3) in an amountof from 0.01 to 1.0 mol %, preferably from 0.02 to 0.9 mol %, morepreferably from 0.03 to 0.85 mol %, with particular preference from 0.04to 0.8 mol %, with very particular preference from 0.05 to 0.75 mol %,and in particular from 0.06 to 0.7 mol %, based in each case on thedouble bonds present in the binder (A3).

[0074] The chemically bonded stabilizer comprises compounds which are orwhich denote sterically hindered nitroxyl radicals (>N—O) whichscavenge free radicals in the modified Denisov cycle.

[0075] Examples of suitable chemically bonded stabilizers are HALScompounds, preferably 2,2,6,6-tetraalkylpiperidine derivatives,especially 2,2,6,6-tetramethylpiperidine derivatives, whose nitrogenatom is substituted by an oxygen atom, alkyl group, alkyl carbonyl groupor alkyl ether group. For further details, reference is made to thetextbook “Lackadditive” [Coatings additives] by Johan Bieleman,Wiley-VCH, Weinheim, N.Y., 1998, pages 293 to 295.

[0076] Examples of suitable starting materials for introducing thechemically bonded stabilizers are HALS compounds, preferably2,2,6,6-tetraalkylpiperidine derivatives, especially2,2,6,6-tetramethylpiperidine derivatives, whose nitrogen atom issubstituted by oxygen atom, alkyl group, alkylcarbonyl group or alkylether group and which contain an isocyanate group or anisocyanate-reactive functional group, especially a hydroxyl group. Anexample of a particularly suitable starting material is the nitroxylradical 2,2,6,6-tetramethyl-4-hydroxypiperidine N-oxide.

[0077] The parent structure is linear, branched, hyperbranched ordendrimeric in structure.

[0078] It may contain multivalent, especially divalent, functionalgroups by means of which the above-described structures and/orstructural units are linked with one another to the parent structure.These groups are generally selected such that they do not disrupt, oreven prevent entirely, the reactions initiated by the actinic radiation.Examples of suitable functional groups are ether, thioether, carboxylicester, thiocarboxylic ester, carbonate, thiocarbonate, phosphoric ester,thiophosphoric ester, phosphonic ester, thiophosphonic ester, phosphite,thiophosphite, sulfonic ester, amide, amine, thioamide, phosphoramide,thiophosphoramide, phosphonamide, thiophosphonamide, sulfonamide, imide,urethane, hydrazide, urea, thiourea, carbonyl, thiocarbonyl, sulfone,sulfoxide or siloxane groups. Of these groups, the ether, carboxylicester, carbonate, carboxamide, urea, urethane, imide and carbonategroups, especially the carboxylic ester and the urethane groups, are ofadvantage and are therefore used with preference.

[0079] Advantageous oligomeric and polymeric parent structures arederived, therefore, from random, alternating and/or block, linear,branched, hyperbranched, dendrimeric and/or comb addition (co)polymersof ethylenically unsaturated monomers, polyaddition resins and/orpolycondensation resins. For further details of these terms, referenceis made to Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag,Stuttgart, New York, 1998, page 457, “Polyaddition” and “Polyadditionresins (Polyadducts)”, and pages 463 and 464, “Polycondensates”,“Polycondensation”, and “Polycondensation resins”.

[0080] Examples of suitable addition (co)polymers arepoly(meth)acrylates and partially hydrolyzed polyvinyl esters.

[0081] Examples of suitable polyaddition resins and/or polycondensationresins are polyesters, alkyds, polyurethanes, polyester-polyurethanes,polylactones, polycarbonates, polyethers, polyester-polyethers, epoxyresin-amine adducts, polyureas, polyamides or polyimides. Of these, thepolyurethanes and polyester-polyurethanes are particularly advantageousand are therefore used with very particular preference in accordancewith the invention.

[0082] The method of preparing the polyurethanes andpolyester-polyurethanes used with preference in accordance with theinvention has no special features but instead takes place with the aidof the apparatus and techniques customary and known in this field.Suitable methods and apparatus are described in detail, for example, inthe patent applications EP 0 089 497 A1, EP 0 228 003 A1, EP 0 354 261A1, EP 0 422 357 A1, EP 0 424 705 A1 or EP 0 299 148 A1.

[0083] The amount of the binders (A2) and/or (A3) in the multicomponentsystems of the invention may also vary very widely. Preferably it isfrom 1 to 50, more preferably from 2 to 45, with particular preferencefrom 3 to 40, with very particular preference from 4 to 35, and inparticular from 5 to 30% by weight, based in each case on the solids ofthe multicomponent system of the invention.

[0084] Furthermore, the isocyanate-reactive binder component (A) mayadditionally comprise at least one further additive.

[0085] Additives suitable in particular for use in liquid 100% systemsare reactive diluents curable thermally and reactive diluents that canbe activated with actinic radiation.

[0086] Where used, the reactive diluents curable thermally are presentin the isocyanate-reactive binder component (A), whereas the reactivediluents than can be activated with actinic radiation may be presentboth in the isocyanate-reactive binder component (A) and in thecrosslinker component (B). Preferably, they are present in the bindercomponent (A).

[0087] The two types of reactive diluent may also act as solvents and/ordispersants for the other constituents of the multicomponent systems ofthe invention.

[0088] Examples of suitable reactive diluents curable thermally arepositionally isomeric diethyloctanediols or hydroxyl-containinghyperbranched compounds or dendrimers, as described in patentapplications DE 198 09 643 A1, DE 198 40 605 A1 or DE 198 05 421 A1.

[0089] Examples of suitable reactive diluents curable by actinicradiation are those described under the headword “Reactive diluents” inRömpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, NewYork, 1998, on page 491. Also suitable are vinylaromatic compounds,especially styrene.

[0090] The proportion of the reactive diluents in the multicomponentsystems of the invention may vary very widely and is guided inparticular by the reactivity which the multicomponent systems areintended to have. They are preferably present in the multicomponentsystems of the invention in an amount of from 5 to 70, preferably from 6to 60, with particular preference from 7 to 55, with very particularpreference from 8 to 50, and in particular from 9 to 45% by weight,based in each case on the solids of the multicomponent system of theinvention.

[0091] Otherwise, the isocyanate-reactive binder component (A) for usein accordance with the invention may comprise color and/or effectpigments and/or electrically conductive pigments, organic and inorganic,transparent or opaque, electrically conductive or nonconductive fillers,nanoparticles, low-boiling organic solvents and high-boiling organicsolvents (“long solvents”), UV absorbers, light stabilizers,free-radical scavengers, thermally labile free-radical initiators,additional crosslinking agents, photoinitiators and photo-coinitiators,additional binders, thermal crosslinking catalysts, devolatilizers, slipadditives, polymerization inhibitors, defoamers, emulsifiers, wettingagents, dispersants, adhesion promoters, leveling agents, film-formingauxiliaries, sag control agents (SCAs), rheology control additives(thickeners), flame retardants, siccatives, dryers, antiskinning agents,corrosion inhibitors, waxes, flatting agents, and precursors oforganically modified ceramic materials or additional binders.

[0092] Examples of suitable effect pigments and/or electricallyconductive pigments are metal flake pigments such as commercial aluminumbronzes, aluminum bronzes chromated in accordance with DE 36 36 183 A1,and commercial stainless steel bronzes, and also nonmetallic effectpigments, such as pearlescent pigments and interference pigments, forexample. For further details, reference is made to Römpp Lexikon Lackeund Druckfarben, Georg Thieme Verlag, 1998, page 176, “Effect pigments”and pages 380 and 381, “Metal oxide-mica pigments” to “Metal pigments”.

[0093] Examples of suitable inorganic color pigments and/or electricallyconductive pigments are titanium dioxide, iron oxides, Sicotrans yellow,and carbon black. Examples of suitable organic color pigments arethioindigo pigments, indanthrene blue, Cromophthal red, Irgazine orangeand Heliogen green. For further details, reference is made to RömppLexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages 180 and181, “Iron blue pigments” to “Black iron oxide”, pages 451 to 453,“Pigments” to “Pigment volume concentration”, page 563, “Thioindigopigments”, and page 567, “Titanium dioxide pigments”.

[0094] For the multicomponent systems of the invention it is ofadvantage to use electrically conductive pigments such as titaniumdioxide/tin oxide pigments, since by this means the multicomponentsystems of the invention may be applied by means of electrostatic sprayapplication (ESTA).

[0095] Examples of suitable organic and inorganic fillers are chalk,dolomite calcium sulfates, barium sulfates, silicates such as talc orkaolin, mica, silicas, oxides such as aluminum hydroxide or magnesiumhydroxide, or organic fillers such as textile fibers, cellulose fibers,polyethylene fibers, or wood flour. For further details, reference ismade to Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998,pages 250 ff., “Fillers”.

[0096] For the multicomponent systems of the invention it is ofadvantage to use mixtures of platelet-shaped inorganic fillers such astalc or mica and nonplatelet-shaped inorganic fillers such as chalk,dolomite calcium sulfates, or barium sulfate, since by this means theviscosity and rheology may be established very effectively.

[0097] Furthermore, it is of advantage for the multicomponent systems ofthe invention to use the fillers, or a fraction of the fillers, in theform of a dispersion in reactive diluents curable with actinicradiation. Examples of suitable additional crosslinking agents are aminoresins, as described, for example, in Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, 1998, page 29, “Amino resins”, in thetextbook “Lackadditive” by Johan Bieleman, Wiley-VCH, Weinheim, NewYork, 1998, pages 242 ff., in the book “Paints, Coatings and Solvents”,second, completely revised edition, Edit. D. Stoye and W. Freitag,Wiley-VCH, Weinheim, New York, 1998, pages 80 ff., in patents U.S. Pat.No. 4,710,542 A1 or EP-B-0 245 700 A1, and in the article by B. Singhand coworkers, “Carbamylmethylated Melamines, Novel Crosslinkers for theCoatings Industry” in Advanced Organic Coatings Science and TechnologySeries, 1991, Volume 13, pages 193 to 207; carboxyl-containing compoundsor resins, as described, for example, in patent DE 196 52 813 A1; resinsor compounds containing epoxide groups, as described, for example, inpatents EP 0 299 420 A1, DE 22 14 650 B1, DE 27 49 576 B1, U.S. Pat. No.4,091,048 A1 and U.S. Pat. No. 3,781,379 A1; blocked polyisocyanates, asdescribed, for example, in patents U.S. Pat. No. 4,444,954 A1, DE 196 17086 A1, DE 196 31 269 A1, EP 0 004 571 A1 and EP 0 582 051 A1; and/ortris(alkoxycarbonylamino)triazines, as described in patents U.S. Pat.No. 4,939,213 A1, U.S. Pat. No. 5,084,541 A1, U.S. Pat. No. 5,288,865 A1and EP 0 604 922 A1.

[0098] Examples of suitable low-boiling organic solvents andhigh-boiling organic solvents (“long solvents”) are ketones such asmethyl ethyl ketone or methyl isobutyl ketone, diols such asbutylglycol, esters such as ethyl acetate, butyl acetate or butyl glycolacetate, ethers such as dibutyl ether or ethylene glycol, diethyleneglycol, propylene glycol, dipropylene glycol, butylene glycol ordibutylene glycol dimethyl, diethyl or dibutyl ether,N-methylpyrrolidone or xylenes or mixtures of aromatic hydrocarbons suchas Solventnaphtha® or Solvesso®.

[0099] Examples of suitable thermally labile free-radical initiators areorganic peroxides, organic azo compounds or C—C-cleaving initiators suchas dialkyl peroxides, peroxocarboxylic acids, peroxodicarbonates,peroxide esters, hydroperoxides, ketone peroxides, azodinitriles, orbenzpinacol silyl ether.

[0100] Examples of suitable crosslinking catalysts are dibutyltindilaurate, lithium decanoate, oleate and/or stearate, or zinc octoate.

[0101] Examples of suitable photoinitiators and coinitiators aredescribed in Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag,Stuttgart, 1998, pages 444 to 446.

[0102] The additional binders differ structurally from the binders (A1),(A2) and (A3). Examples of suitable additional binders are oligomericand polymeric, linear and/or branched and/or block, comb and/or randomaddition (co)polymers of ethylenically unsaturated monomers, orpolyaddition resins and/or polycondensation resins, such aspoly(meth)acrylates or acrylate copolymers, polyesters, alkyds,acrylated polyesters, polylactones, polycarbonates, polyethers, epoxyresin-amine adducts, (meth)acrylate diols, partially hydrolyzedpolyvinyl esters, polyurethanes and acrylated polyurethanes,polyester-polyurethanes or polyureas.

[0103] Examples of suitable devolatilizers are diazadicycloundecane andbenzoin.

[0104] Examples of suitable emulsifiers are nonionic emulsifiers, suchas alkoxylated alkanols and polyols, phenols and alkylphenols, oranionic emulsifiers such as alkali metal salts or ammonium salts ofalkane carboxylic acids, alkanesulfonic acids and sulfo acids ofalkoxylated alkanols and polyols, phenols and alkylphenols.

[0105] Examples of suitable wetting agents are siloxanes, fluorinecompounds, carboxylic monoesters, phosphoric esters, polyacrylic acidsand their copolymers, or polyurethanes.

[0106] An example of a suitable adhesion promoter istricyclodecanedimethanol.

[0107] Examples of suitable of film-forming auxiliaries are cellulosederivatives such as cellulose acetobutyrate (CAB).

[0108] Examples of suitable transparent fillers and/or nanoparticles arethose based on silica, alumina or zirconium oxide; for further details,reference is made to Römpp Lexikon Lacke und Druckfarben, Georg ThiemeVerlag, Stuttgart, 1998, pages 250 to 252.

[0109] Examples of suitable sag control agents are ureas, modified ureasand/or silicas, as described, for example, in the literature referencesEP 0 192 304 A1, DE 23 59 923 A1, DE 18 05 693 A1, WO 94/22968, DE 27 51761 C1, WO 97/12945 or “farbe+lack”, 11/1992, pages 829 ff.

[0110] Examples of suitable rheology control additives are those knownfrom patents WO 94/22968, EP 0 276 501 A1, EP 0 249 201 A1 or WO97/12945; crosslinked polymeric microparticles, as disclosed, forexample, in EP 0 008 127 A1; inorganic phyllosilicates such asaluminum-magnesium silicates, sodium-magnesium andsodium-magnesium-fluorine-lithium phyllosilicates of the montmorillonitetype; silicas such as Aerosils; or synthetic polymers containing ionicand/or associative groups, such as polyvinyl alcohol,poly(meth)acrylamide, poly(meth)acrylic acid, polyvinyl-pyrrolidone,styrene-maleic anhydride or ethylene-maleic anhydride copolymers andtheir derivatives, or hydrophobically modified ethoxylated urethanes orpolyacrylates.

[0111] An example of a suitable flatting agent is magnesium stearate.

[0112] Examples of suitable precursors of organically modified ceramicmaterials are hydrolyzable organometallic compounds, especially those ofsilicon and aluminum.

[0113] Further examples of the abovementioned additives and alsoexamples of suitable UV absorbers, free-radical scavengers, levelingagents, flame retardants, siccatives, dryers, antiskinning agents,corrosion inhibitors and waxes are described in detail in the text book“Lackadditive” by Johan Bieleman, Wiley-VCH, Weinheim, New York, 1998.

[0114] The isocyanate-reactive binder component (A) for use inaccordance with the invention may itself be present in the form of amulticomponent system, i.e., with its constituents as described abovebeing stored separately from one another until use. For example, thebinders (A1) may be stored separately from the binders (A2) and/or (A3).In accordance with the invention, however, it is of advantage to collecttogether all constituents in an isocyanate-reactive binder component(A). Where the crosslinker component (B) likewise forms a component inthe above sense, this results in the two-component system of theinvention.

[0115] Viewed in terms of its method, the preparation of theisocyanate-reactive binder component (A) for use in accordance with theinvention has no special features but instead takes place with the aidof the customary and known apparatus and techniques for the preparationof powder coating materials, powder slurries, liquid 100% systems,aqueous coating materials or conventional coating materials, usingcustomary and known mixing equipment such as stirred vessels,dissolvers, including in-line dissolvers, toothed-wheel dispersers,stirred mills, or extruders.

[0116] The other constituent of the multicomponent system of theinvention that is essential to the invention is at least one crosslinkercomponent (B).

[0117] The crosslinker component comprises at least one polyisocyanate(B1).

[0118] There is basically no upper limit on the number of isocyanategroups in the polyisocyanates (B1); in accordance with the invention,however, it is of advantage if the number does not exceed 15, preferably12, with particular preference 10, with very particular preference 8.0,and in particular 6.0.

[0119] Examples of suitable polyisocyanates (B1) are polyurethaneprepolymers which contain isocyanate groups, may be prepared by reactingpolyols with an excess of preferably aliphatic and cycloaliphaticdiisocyanates, and are preferably of low viscosity. In the context ofthe present invention, the term “cycloaliphatic diisocyanate” refers toa diisocyanate in which at least one isocyanate group is attached to acycloaliphatic radical.

[0120] Examples of suitable cycloaliphatic diisocyanates are isophoronediisocyanate (i.e.,5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane),5-isocyanato-1-(2-isocyanatoeth-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-1-(3-isocyanatoprop-1-yl)-1,3,3-trimethylcyclohexane,5-isocyanato-(4-isocyanatobut-1-yl)-1,3,3-trimethylcyclohexane,1-isocyanato-2-(3-isocyanatoprop-1-yl)cyclohexane,1-isocyanato-2-(3-isocyanatoeth-1-yl)cyclohexane,1-isocyanato-2-(4-isocyanatobut-1-yl)cyclohexane,1,2-diisocyanatocyclobutane, 1,3-diisocyanatocyclobutane,1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane,1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane,1,4-diisocyanatocyclohexane, dicyclohexylmethane 2,4′-diisocyanate ordicyclohexylmethane 4,4′-diisocyanate, especially isophoronediisocyanate.

[0121] Examples of suitable acyclic aliphatic diisocyanates aretrimethylene diisocyanate, tetramethylene diisocyanate, pentamethylenediisocyanate, hexamethylene diisocyanate, ethyl ethylene diisocyanate,trimethylhexane diisocyanate, heptanemethylene diisocyanate ordiisocyanates derived from dimeric fatty acids, as marketed by Henkelunder the commercial designation DDI 1410 and described in patents WO97/49745 and WO 97/49747, especially2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentylcyclohexane, or 1,2-, 1,4-or 1,3-bis-(isocyanatomethyl)cyclohexane, 1,2-, 1,4- or1,3-bis(2-isocyanatoeth-1-yl)cyclohexane,1,3-bis(3-isocyanatoprop-1-yl)cyclohexane or 1,2-, 1,4- or1,3-bis(4-isocyanatobut-1-yl)cyclohexane.

[0122] Of these, hexamethylene diisocyanate is of particular advantageand is therefore used with very particular preference in accordance withthe invention.

[0123] It is also possible to use polyisocyanates (B1) containingisocyanurate, biuret, allophanate, iminooxadiazinedione, urethane, urea,carbodiimide and/or uretdione groups, these polyisocyanates beingprepared in customary and known manner from the diisocyanates describedabove. Examples of suitable preparation processes and polyisocyanatesare known, for example, from patents and patent applications CA2,163,591 A, US 4,419,513 A, US 4,454,317 A, EP 0 646 608 A1, US4,801,675 A, EP 0 183 976 A1, DE 40 15 155 A1, EP 0 303 150 A1, EP 0 496208 A1, EP 0 524 500 A1, EP 0 566 037 A1, US 5,258,482 A, US 5,290,902A, EP 0 649 806 A1, DE 42 29 183 A1 and EP 0 531 820 A1.

[0124] Instead of or in addition to the polyisocyanates (B1), thecrosslinker component (B) for use in accordance with the inventioncontains at least one polyisocyanate (B2) whose molecule comprises onaverage at least one, preferably at least two, of the above-describedradiation-active groups.

[0125] The polyisocyanates (B2) are obtainable by reacting theabove-described polyisocyanates (B1) with compounds containing at leastone, especially one, of the above-described bonds that can be activatedwith actinic radiation and at least one, especially one, of theabove-described isocyanate-reactive groups.

[0126] Examples of suitable compounds which contain at least one bondthat can be activated with actinic radiation and at least oneisocyanate-reactive group are the following:

[0127] allyl alcohol or 4-butyl vinyl ether;

[0128] hydroxyalkyl esters of acrylic acid or methacrylic acid,especially of acrylic acid, obtainable by esterifying aliphatic diols ofacrylic acid or methacrylic acid or by reacting acrylic acid ormethacrylic acid with an alkylene oxide, especially hydroxyalkyl estersof acrylic acid or methacrylic acid in which the hydroxyalkyl groupcontains up to 20 carbon atoms, such as 2-hydroxyethyl, 2-hydroxypropyl,3-hydroxypropyl, 3-hydroxybutyl, 4-hydroxybutyl, andbis(hydroxymethyl)cyclohexane acrylate or methacrylate; of these,2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularlyadvantageous and are therefore used with particular preference inaccordance with the invention; or

[0129] reaction products of cyclic esters, such as epsilon-caprolactone,for example, and these hydroxyalkyl or hydroxycycloalkyl esters.

[0130] The polyisocyanates (B1) are reacted with the compoundscontaining at least one bond that can be activated with actinicradiation and at least one isocyanate-reactive group in a molar ratiosuch that on average at least one free isocyanate group remains permolecule.

[0131] Viewed in terms of method, this reaction has no special featuresbut instead takes place as described, for example, in European Patent EP0 928 800 A1.

[0132] In accordance with the invention it is of advantage to use thepolyisocyanates (B2) in the multicomponent systems of the invention,since the systems are then able to participate in the dual cure curingmechanism.

[0133] The crosslinker component (B) may further comprise at least oneof the above-described additives, provided it is notisocyanate-reactive. It is preferred to use inert organic solvents ifthe viscosity of the crosslinker component (B) is to be alteredspecifically, especially if it is to be reduced, in order to facilitateits incorporation into the binder component (A).

[0134] The amount of the polyisocyanates (B1) and/or (B2) for use inaccordance with the invention in the multicomponent systems of theinvention may vary very widely. It is guided in particular by thefunctionality and the amount of the isocyanate-reactive binder component(A). The amount is preferably from 1 to 50, more preferably from 2 to45, with particular preference from 3 to 40, with very particularpreference from 4 to 35, and in particular from 5 to 30% by weight,based in each case on the solids of the multicomponent system of theinvention.

[0135] The preparation of the multicomponent system of the inventionfrom the isocyanate-reactive binder component (A) and the crosslinkercomponent (B) also has no special features as to method but insteadtakes place in accordance with the customary and known methods, forexample, by manual mixing or mechanical mixing in suitable mixingequipment such as stirred vessels, toothed-gear dispersers orhomogenizing nozzles.

[0136] Although the multicomponent systems of the invention are suitablefor all applications in the fields of coating, especially in OEMautomotive finishing, in automotive refinishing, in the coating ofinterior and exterior constructions, in the coating of furniture, doors,or windows, in industrial coating, including coil coating and containercoating, and in the coating on and/or impregnation of electricalcomponents, in which they may be used to produce primer coats, surfacercoats, color and/or effect topcoats and basecoats or clearcoats, theydevelop their particular advantages in connection with the priming ofplastics parts.

[0137] The plastics parts may be of plastic such as ABS, AMMA, ASA, CA,CAB, EP, UF, CF, MF, MPF, PF, PAN, PA, PE, HDPE, LDPE, LLDPE, UHMWPE,PET, PMMA, PP, PS, SB, PUR, PVC, RF, SAN, PBT, PPE, PPE/PS, PA, PPE/PA,POM, PUR-RIM, SMC, BMC, PP-EPDM and UP (abbreviations in accordance withDIN 7728P1), polymer blends thereof or the corresponding glass fiberreinforced or carbon fiber reinforced plastics. Preferably, plasticsparts as commonly used in motor vehicle bodywork construction are coatedor primed with the multicomponent systems of the invention.

[0138] The application of the multicomponent system of the invention maytake place by all customary application methods, such as spraying, knifecoating, brushing, flow coating, dipping, impregnating, trickling orroller coating. The substrate to be coated may per se be at rest, withthe application equipment or unit being moved. Alternatively, thesubstrate to be coated, especially a coil, may be moved, with theapplication unit being at rest relative to the substrate or being movedin an appropriate manner.

[0139] Preference is given to the use of spray application methods, suchas compressed air spraying, airless spraying, high-speed rotation, orelectrostatic spray application (ESTA), for example.

[0140] Application is preferably conducted under illumination withvisible light of a wavelength of more than 550 μm or in the absence oflight. This prevents material changes or damage to the multicomponentsystem of the invention.

[0141] In general, the multicomponent system of the invention is appliedin a wet film thickness such that curing thereof results in primer coatshaving the thicknesses advantageous and necessary for their functions.The coat thicknesses are preferably from 5 to 100, more preferably from6 to 90, with particular preference from 7 to 80, with very particularpreference from 8 to 70, and in particular from 9 to 60 μm.

[0142] In the context of the process of the invention, the film of themulticomponent system of the invention, following its application, iscured thermally and with actinic radiation.

[0143] In the context of the process of the invention, curing may takeplace directly after the application of the film of the multicomponentsystem of the invention.

[0144] Alternatively, curing may take place after a certain resting timeor flashoff time. Such a time may last for from 30 s to 2 h, preferablyfrom 1 min to 1 h, and in particular from 1 min to 45 min. The restingtime is used, for example, for the leveling and degassing of the filmsand for the evaporation of volatile constituents such as any solventstill present.

[0145] In the case of curing with actinic radiation, it is preferred toemploy a dose of from 1000 to 3000, preferably from 1100 to 2900, withparticular preference from 1200 to 2800, with very particular preferencefrom 1300 to 2700, and in particular from 1400 to 2600 mJ/cm². Ifdesired, this curing may be supplemented by actinic radiation from otherradiation sources. In the case of electron beams, it is preferred tooperate under an inert gas atmosphere. This can be ensured, for example,by supplying carbon dioxide and/or nitrogen directly to the surface ofthe film. In the case of curing with UV radiation, as well, it ispossible to operate under inert gas in order to prevent the formation ofozone.

[0146] Curing with actinic radiation is carried out using the customaryand known radiation sources and optical auxiliary measures. Examples ofsuitable radiation sources are flashlights from the company VISIT,high-pressure or low-pressure mercury vapor lamps, with or without leaddoping in order to open a radiation window of up to 405 nm, or electronbeam sources. The arrangement of these sources is known in principle andmay be adapted to the circumstances of the workpiece and the processparameters. In the case of workpieces of complex shape, as are providedfor automobile bodies, those regions not accessible to direct radiation(shadow regions), such as cavities, folds and other structuralundercuts, may be cured using point, small-area or all-round emitters,in combination with an automatic movement apparatus for the irradiationof cavities or edges.

[0147] The equipment and conditions for these curing methods aredescribed, for example, in R. Holmes, U.V. and E.B. Curing Formulationsfor Printing Inks, Coatings and Paints, SITA Technology, Academic Press,London, United Kingdom, 1984.

[0148] Full curing may take place here in stages, i.e., by multipleexposure to light or actinic radiation. It can also take place inalternation, in other words, by curing alternately with UV radiation andelectron beams.

[0149] Thermal curing also has no special features in terms of itsmethod but instead takes place in accordance with the customary andknown methods such as heating in a convection oven or irradiation withIR or NIR lamps. As in the case of curing with actinic radiation,thermal curing may also take place in stages. Advantageously, thermalcuring takes place at temperatures below 100° C., preferably 90° C. Withparticular preference, thermal curing is conducted at between 40 and 80°C.

[0150] Thermal curing and curing with actinic radiation are employedsimultaneously or in succession. If the two curing methods are used insuccession, it is possible, for example, to commence with thermal curingand end with actinic radiation curing. In other cases, it may proveadvantageous to commence and to end with actinic radiation curing.

[0151] If desired, the dual cure may also be supplemented, orterminated, by storage under hot conditions, for example, at from 40 to80° C. for an hour or for up to several days.

[0152] The particularly advantageous properties of the multicomponentsystem of the invention permit transit speeds of 10 m/min or more. Owingto the mild conditions which can be employed for curing, primer coats inautomotive class A surface quality are obtained despite highproductivity. Following their mounting on the motor vehicle bodies,immediately or after storage for any period of time, the mountedplastics parts primed in accordance with the invention withstand allcustomary processes of automotive coating, such as electrodepositioncoating or coating with surfacers, basecoats, clearcoats or solid-colortopcoats.

[0153] The fully painted mounted plastics parts primed in accordancewith the invention have an outstanding surface and also excellentoptical properties. The adhesion of the primer of the invention to theplastics surface, on the one hand, and to the coating present on it, onthe other, is outstanding. The mounted plastics parts primed inaccordance with the invention therefore meet all of the requirements ofmodern motor vehicle painting.

EXAMPLES Preparation Example 1 The Preparation of the MonocarboxylicAcid (VII)

[0154] A stirring flask with heating system and reflux condenser wascharged with the following:

[0155] 710.81 g of dicyclopentadiene (93 percent) (5.0 mol) and

[0156] 490.30 g of maleic anhydride (5.0 mol).

[0157] The mixture was heated to 125° C. under a gentle stream ofnitrogen. Subsequently, 95.00 g of water (5.0 mol + 5 g)

[0158] were added from a dropping funnel over the course of one hour.Reaction was allowed to continue at 125° C. for one hour. Themonocarboxylic acid (VII) was formed:

Preparation Example 2 The Preparation of Polyester (A1) for Use inAccordance with the Invention

[0159] A stirring flask equipped with heating system and top-mounteddistillation unit was charged with the following starting compounds:

[0160] 315.00 g of triethylene glycol (2.1 mol),

[0161] 134.00 g of diethylene glycol monoethyl ether (1 mol),

[0162] 516.80 g of the monocarboxylic acid (VII) of Preparation Example1 (2 mol),

[0163] 156.60 g of fumaric acid (1.35 mol),

[0164] 87.36 g of di(ethylhexyl) benzophenonetetracarboxylate (0.15mol),

[0165] 4.00 g of Fascat® 4201 (commercial esterification catalyst), and

[0166] 0.50 g of hydroquinone.

[0167] The reaction mixture was heated rapidly to 130° C. under a gentlestream of nitrogen. Subsequently, the temperature was raised graduallyto 190° C. over the course of 4.5 hours. During this time, the water ofcondensation formed was removed by distillation.

[0168] This gave a liquid polyester (A1) having an acid number of 9.7 mgKOH/g, a hydroxyl number of 59 mg KOH/g and a viscosity and 7220 mPas at25° C.

Preparation Example 3 The Preparation of a Polyester (A1) for Use inAccordance with the Invention, Having Enhanced Flexibility

[0169] A stirring flask equipped with heating system and top-mounteddistillation unit was charged with the following starting compounds:

[0170] 1441.5 g of maleic anhydride (17.7 mol),

[0171] 546.6 g of Imidol 6 (diethanolamine maleimide) (2.8 mol), and

[0172] 56 g of water (3.1 mol).

[0173] The initial charge was heated to 90° C., whereupon an exothermicreaction took place.

[0174] Immediately thereafter, the feed stream 1 (398 g ofdicyclopentadiene, 93 percent, 2.8 mol) was metered in to the initialcharge at from 116 to 128° C. over the course of 30 minutes. Theresulting mixture was held at 125° C. for one hour.

[0175] Thereafter, the heating system was removed and a mixtureconsisting of

[0176] 491.0 g of castor oil (hydroxyl number: 160 mg KOH/g),

[0177] 1040.0 g of 2-methyl-1,3-propanediol (11.58 mol), and

[0178] 7.4 g of Fascat® 4201

[0179] was incorporated by stirring. The resulting reaction mixture washeated rapidly to 130° C. under a gentle stream of nitrogen. Then thetemperature was raised gradually to 190° C. over the course of 6 hours,during which the water of condensation formed was removed bydistillation.

[0180] This gave a liquid polyester (A1) having an acid number of 7.8 mgKOH/g and a hydroxyl number of 92 mg KOH/g and a viscosity of 224 Pas at25° C.

Example 1 The Preparation of Two-component System of the Invention

[0181] The binder component (A) was prepared by mixing the constituentsindicated below, in the stated order, in a high-speed dissolver:

[0182] 50 parts by weight of styrene,

[0183] 36 parts by weight of the polyester (A1) of Preparation Example2,

[0184] 22 parts by weight of Ebecryl® IRR 351 [(A3); commercialhydroxyl-containing polyurethane acrylate from UCB],

[0185] 12 parts by weight of Talkum AT,

[0186] 16.4 parts by weight of dolomite,

[0187] 10 parts by weight of Dental® W 500 (commercial, electricallyconductive titanium dioxide/tin oxide pigment from Otosuka Ltd.),

[0188] 0.4 part by weight of Irgacure® 184 (commercial photoinitiator),

[0189] 4 parts by weight of Aerosil® 200 gel (commercial pyrogenicsilica, 10 percent in styrene),

[0190] 6 parts by weight of Bentone® gel (commercial bentonite, 10percent in styrene),

[0191] 0.2 part by weight of Disparlon® LC 900 (commercial wetting agentfrom Kosumoto Ltd.), and

[0192] 0.4 part by weight of Nuodex® Li (commercial catalyst for thermalcrosslinking NCO/OH).

[0193] The resulting binder component (A) was completely stable onstorage.

[0194] The binder component (A) was mixed with 27 parts by weight of thecommercial polyisocyanate Roskydal® 2337 from Bayer AG (B2), whichcontained acrylate groups.

[0195] The resulting two-component system of the invention had a potlife or processing time of more than 36 hours. Nevertheless, it wasfully cured by irradiation with UV light within five minutes followingits pneumatic application with a gravity-feed gun to plastics parts at60° C. This gave primer coats of the invention having a dry thickness of30 μm. These coats had an outstanding, smooth surface and outstandingadhesion to the plastics surfaces. Moreover, they could be painted overwithout problems. The intercoat adhesion was likewise outstanding.

Example 2 The Preparation of a Two-component System of the Invention

[0196] The binder component (A) was prepared by mixing the constituentsindicated below, in the stated order, in a high-speed dissolver:

[0197] 50 parts by weight of hexanediol diacrylate,

[0198] 42 parts by weight of the polyester (A1) of Preparation Example3,

[0199] 17 parts by weight of Ebecryl® IRR 351 [(A3); commercialhydroxyl-containing polyurethane acrylate from UCB],

[0200] 12 parts by weight of Talkum AT,

[0201] 16.4 parts by weight of dolomite,

[0202] 10 parts by weight of Dental® W 500 (commercial, electricallyconductive titanium dioxide/tin oxide pigment from Otosuka Ltd.),

[0203] 1.9 parts by weight of Irgacure® 1850 (commercialphotoinitiator),

[0204] 4.5 parts by weight of Aerosil® 200 gel (commercial pyrogenicsilica, 10 percent in styrene),

[0205] 5.5 parts by weight of Bentone® gel (commercial bentonite, 10percent in styrene),

[0206] 0.3 part by weight of Disparlon® LC 900 (commercial wetting agentfrom Kosumoto Ltd.), and

[0207] 0.4 part by weight of Nuodex® Li (commercial catalyst for thermalcrosslinking NCO/OH).

[0208] The resulting binder component (A) was completely stable onstorage.

[0209] The binder component (A) was mixed with 31 parts by weight of thecommercial polyisocyanate Roskydal® 2337 from Bayer AG (B2), whichcontained acrylate groups.

[0210] The resulting two-component system of the invention likewise hada pot life or processing time of more than 36 hours. Nevertheless, itwas fully cured by irradiation with UV light within 6 minutes followingits pneumatic application with a gravity-feed gun to plastics parts at60° C. This gave primer coats of the invention having a dry thickness of55 μm. These coats had an outstanding, smooth surface and outstandingadhesion to the plastics surfaces. Moreover, they could be painted overwithout problems. The intercoat adhesion was likewise outstanding.

1. A multicomponent system curable thermally and with actinic radiation,comprising A) an isocyanate-reactive binder component comprising A1) atleast one unsaturated polyester whose molecule contains on average atleast one group that can be activated with actinic radiation, of theformulae I, II and/or III

(II),in which the index n is an integer from 1 to 10;

 and A2) at least one binder, different than the polyester (A1), whosemolecule comprises on average at least two isocyanate-reactivefunctional groups,  and/or A3) at least one binder, different than thepolyester (A1), whose molecule comprises on average at least oneisocyanate-reactive functional group and at least one reactivefunctional group having at least one bond that can be activated withactinic radiation,  and B) a crosslinker component comprising B1) atleast one polyisocyanate and/or B2) at least one polyisocyanate whosemolecule comprises on average at least one reactive functional grouphaving at least one bond that can be activated with actinic radiation.2. The multicomponent system as claimed in claim 1, characterized inthat the binder component (A) comprises at least one reactive diluentcurable thermally.
 3. The multicomponent system as claimed in claim 1 or2, characterized in that the binder component (A) and/or the crosslinkercomponent (B) comprise/comprises at least one reactive diluent that canbe activated with actinic radiation.
 4. The multicomponent system asclaimed in any of claims 1 to 3, characterized in that the bonds thatcan be activated with actinic radiation comprise carbon-hydrogen singlebonds or carbon-carbon, carbon-oxygen, carbon-nitrogen,carbon-phosphorus or carbon-silicon single bonds or double bonds,especially carbon-carbon double bonds.
 5. The multicomponent system asclaimed in claim 4, characterized in that the bonds that can beactivated with actinic radiation comprise carbon-carbon double bonds. 6.The multicomponent system as claimed in claim 5, characterized in thatthe carbon-carbon double bonds are present in (meth)acrylate,ethacrylate, crotonate, cinnamate, vinyl ether, vinyl ester,dicyclopentadienyl, norbornenyl, isoprenyl, isoprenyl, isopropenyl,allyl and/or butenyl groups; dicyclopentadienyl, norbornenyl, isoprenyl,isopropenyl, allyl and/or butenyl ether groups, or dicyclopentadienyl,norbornenyl, isoprenyl, isopropenyl, allyl and/or butenyl ester groups.7. The multicomponent system as claimed in any of claims 1 to 6,characterized in that hydroxyl, amino and/or thiol groups are used asisocyanate-reactive functional groups.
 8. The multicomponent system asclaimed in claim 7, characterized in that hydroxyl groups are used. 9.The multicomponent system as claimed in any of claims 1 to 8,characterized in that it comprises at least one platelet-shaped and atleast one nonplatelet-shaped inorganic filler.
 10. The multicomponentsystem as claimed in any of claims 1 to 9, characterized in that itcomprises at least one electrically conductive pigment and/or at leastone electrically conductive filler.
 11. The use of the multicomponentsystem as claimed in any of claims 1 to 10 for priming plastics parts.12. The use as claimed in claim 11, characterized in that said plasticsparts comprise motor vehicle bodies or parts thereof.